Process of electrolyzing aqueous solutions of stannic chlorid.



U NITED STATES PATENT OFFICE.

IEHANZ VON KllGELGEN, OF HOLCOMBS ROCK, VIRGINIA, AND GEORGE O. SEWARD, OF

I'lEW YORK, N. Y.

PROCESS or ELECTRQLYZIYNG Aqueous SOLUTIONS on s'r ANmc cnnonin.

Specification of Letters Patent.

, FatentedMi-arch 24-, 1908.

Application an June 10, new. Serial in).- 378,295.

To all whom it may concern: I

Be it known that we, FRANZ VON Kristin can, a sub ect of the Emperorof Germany, residing at Holcombs Rock, Virginia, and

Gnonen O. 'SEWARD, a citizen of the United.

with insoluble anodes. Such electrolysis proceeds smoothly at first, but after a time the anolyte becomes basic and the catholyte acid, decreasing the current efficiency, while a gelatinous precipitate may deposit in the anode compartment. This resu t is due to the fact that stannic chlorid is partially hydrolyzed by water, with the production of stannic hydroxid and hydrochloric acid, which are therefore present' in the electrolyte. The difference in the ionic velocities causes the concentration of the base and acid in the cell compartments to gradually change during stannic hydroxid in the anode compartment is in excess of that which will remain in solutionin the hydrated stannic chlorid.

' According to the present invention, an aqueous solution of stannic chlorid is electrolyzed in a diaphragm cell, but: the electrolysis-is. not carried so far asto cause the stannic hydroxid to precipitate in the anode compartment. Before this result occurs and when the current-eflicicncy begins to notably drop, the electrolyte is discharged from both compartments of the cell, the anolyte containing stannic hydroxid and catholyte containing hydrochloric acid are mixed, and the mixture is concentrated by boiling it down to a density of about 1.4" to'1.5 Baurn, whereby the stannic hydroxid. and hydrochloric acid are combined with the production of stannic chlorid. The resultant solution is then returned to the electrolytic cell and supplied, either at intervals or continuously, to its several compartments,

electrolysis, until the amount of i We claim:

1. The rocess of electrolyzing aqueous solutions o stannic chlorid, which consists in conducting the electrolysis in a diaphragm cell and combining the stannic hydroxid. and

hydrochloric acid present in the anolyte and catholyte, res i ectively.

2,'The recess of electrolyzing aqueous solutions o stannic chlori'd, which consists in conducting the electrolysis in a diaphragm cell until stannic hydroxid and. hydrochloric acid. accumulate in the anolyte and catholyte, respectively, removing the electrolyte from the cell, and combining the accumulated stannic hydroxid and hydrochloric acid.

with the production of stannic chlorid.

3. The rocess of electrolyzing aqueous solutions '0 stannic chlorid, which consists in conducting the electrolysis in a diaphragm cell until stannichydroxid and hydrochloric acid accumulate in the anolyte andcatliiodyto, respectively, removing the electrolytefrom the cell, and combining the accumulated stannic hydroxid and hydrochloric acid with the production. oi stannic chlorid. by mixing the anolyte and oath olyte and eyapm rating the mixture. l

4. The process of electrolyzing aqueous solutions of stannic chlorid, which consists in conducting the electrolysis in a diaphragm cell until stannic hydroxid and hydrochloric acid accumulate in the anolyte and catholyte, respectively, removine the electrolyte from the cell, and combining the accumulated stannic hydroxid and hydrochloric acid with the production of stannic chlcrid by mixing the anolyte and catholyte and ovaporatingthe mixture to a density of about 1.4 to 1.5 degrees Baum.

5. T he process of clectrolyziug aqueous solutions oi stannic chlorid, which consists in conducting the electrolysis in a diaphragm cell until stannic nydroxid and hydrochloric acid accumulate in the anolyte and catho lytc, respectively, removing the electrolyte from the cell, combining the accumulated stannic hydroxid and hydrochloric acid with the production of stannic chlorid by mixing the anolyte and catholyte and evaporating}. the mixture, and returning the product to the electrolytic cell.

6. The process of olcctrolyaing; aqueous hydroxid and hydrochloric acid with the conductingthe electrolysis in a diaphragm 1 tures inpresence of Witnesses.

greesr Baum, and returning the product tosolutions of'stannic chlorid,-Which consists in In testimony whereof We affix our signa- FRANZ- VON KUGELGEN;

GEORGE o. SEWARD.

cell until stanni'c hydroxid and hydrochloric acid accumulate in theanolyte-and'catliolyte, respec'tively,.removing the electrolyte from the cell, combining the'eccumuleted stannic Kr'igelgen:

HARRY RILEY LEE production of'stannic chlorid by'mixing the i J. H. WEBB. anolyte' and catholyte .and evaporating the Witnesses'es to the signature of Georgc'O. mixture to a density of about 1.4 to 1.5 dei SeWerdi JUSTIN C. WALKER, GEO. FFSEXVARIL thelectrolytic cell. I g

\Vitnesses asto the signature of Franz von 

